Levulinic acid, also referred to as acetyl-propionic acid or 4-oxopentanoic acid, is known as a preservative and as an acidulant that is useful in carbonated and fruit juice beverages, jams, and jellies. It is also used as a starting product for a variety of organic chemicals, including plasticizers, solvents, and pharmaceutical compounds. For example, levulinic acid has been used to produce methyltetrahydrofuran, a fuel additive, and delta-amino levulinic acid, a broad-spectrum herbicide and pesticide.
Levulinic acid is commonly produced by reacting carbohydrates with mineral acids. Known starting materials for producing levulinic acid include molasses, fructose, food starches (e.g., tapioca meal or potatoes), and cellulosic materials such as wood, bagasse, or waste paper. The acid treatment typically yields an aqueous mixture containing levulinic acid, formic acid, and furfural, but being essentially free of glucosamine.
A variety of approaches have been proposed for separating levulinic acid from formic acid and furfural. For example, International Publication No. WO 98/19986 (Farone et al.) proposes separating levulinic acid from furfural and residual sulfuric acid by simulated moving bed chromatography. U.S. Pat. No. 5,859,263 (Ghorpade et al.) suggest preparing levulinic acid from corn starch and sulfuric acid via reactive extrusion. The levulinic acid in the resultant extrudate is removed by a filter press and steam distillation.